1. Field of the Invention
The present invention relates to a left-turn driving support device where vehicles travel on the left side of a road. The device supports a driver""s judgement on making a left turn by communicating driving information such as a left turn and a right turn of a second oncoming vehicle following the forefront oncoming vehicle, which are about to enter the intersection, to the driver of the left-turn vehicle. Adjustment needs to be made where vehicles travel on the right side of a road.
In the present invention, oncoming vehicles mean oncoming vehicles approaching the intersection in the opposite lane, the forefront oncoming vehicle means the first vehicle in the opposite lane, which is arriving at the intersection, and the second vehicle means a vehicle, which follows the forefront oncoming vehicle. Vehicles mean all the vehicles prescribed in traffic regulations.
2. Description of the Related Art
Prior to the present invention, means for supporting a driver making a left turn in an intersection are typically to provide a left-turn only lane, to provide a time-difference control for securing the safety of left-turn vehicles by switching a green traffic signal for the oncoming traffic to a yellow signal to a red signal earlier than a green signal for the traffic lane on the left-turn vehicle side, and to provide traffic signals with left-turn only arrows for the left-turn vehicles for securing the safety of left-turn vehicles.
There are, however, many intersections with traffic signals without the above-mentioned controls supporting left turns, or without traffic signals. In these intersections, the driver making a left turn has to make the judgment of whether the forefront oncoming vehicle goes straight on, turns left or turns right by looking at blinking signals of the forefront oncoming vehicle. If the forefront oncoming vehicle is through traffic or is turning right, the driver making a left turn is able to judge that it is safe to make a left turn by looking at the traveling distance from the oncoming vehicle and makes a left turn. If the forefront oncoming vehicle is making a left turn, the driver makes a left turn at ease. Since the judgement of making a left turn in such cases depends on the judgement of the driver who makes the left turn, it hardly need be said that there are judgement mistakes when making a left turn, and accidents between left-turn vehicles and oncoming through traffic occur frequently. If the second oncoming vehicle is about to make a left turn or a right turn (where it is easier for a left-turn vehicle to make a left turn than in a case where the second oncoming vehicle is about to go straight), it is out of the line of vision (obstructed by the forefront oncoming vehicle) of the driver of the waiting left-turn vehicle, and often he/she cannot visually check the vehicle""s turn signals. Particularly, it is impossible for the driver of the waiting left-turn vehicle to see the turn signals if the forefront oncoming vehicle is a large-sized car.
Prior to the present invention, as technologies supporting making a left turn of a vehicle, there are, for example, in Japanese Patent Laid-open No. 1984-198000, a technology for securing the safety of a vehicle making a left turn by measuring time between a left-turn vehicle and the oncoming vehicle traveling before or after the left-turn vehicle and displaying the result of a calculation on a displaying device installed on the street by calculating whether making a left turn is possible or not based on the time measured, in Japanese Patent Laid-open No. 1993-2700, a technology for supporting making a left turn only when the driver of a left-turn vehicle cannot judge whether to make a left turn to support making a left turn by determining a possibility of a collision with the oncoming through traffic and by issuing an alarm inside the left-turn vehicle if a possibility of a collision exists, and in Japanese Patent Laid-open No. 1997-270097, a technology for creating information to judge to make a left turn by calculating whether a left-turn vehicle can make a left turn safely based on a traveling position of the oncoming through traffic from image signals received from an image sensor installed near an intersection and displayed data at a point of time from a signal controller controlling traffic signal lights and transmitting this information to a receiver installed in the left-turn vehicle for making the judgment to make a left turn. All of these technologies use microcomputer-based controls. As those which do not use the controls, there are technologies such as that in Japanese Patent Laid-open No. 1999-345395, a technology for preventing a collision with the above-mentioned second oncoming vehicle by installing a downward-looking concave mirror at the upper portion of a post set up near the traffic light of an intersection, widely reflecting objects passing through the street and allowing waiting left-turn vehicles to visually recognize a second oncoming vehicle following a first oncoming vehicle, particularly a large-sized vehicle, being making a left turn at the intersection, where the second oncoming vehicle is passing the side of the first oncoming left-turn vehicle to avoid the above-mentioned left-turn vehicle.
The above-mentioned conventional left-turn support devices basically intend to support making a left turn of a forefront vehicle entering an intersection. Because those devices include expensive controls such as microcomputers, their structure is complex and managing them is complicated. Additionally, in the case of the device using a concave mirror, if it extensively reflects the road surface, vehicles reflected were small and there was some possibility of failing to notice the second oncoming vehicle.
As a result of particularly examining traveling conditions at the intersection of a two-lane road, the inventors of the present invention found that not many accidents occurred between a vehicle making a left turn and a forefront oncoming vehicle on a road where the traffic is light, because the driver of the vehicle waiting to make a left turn can directly visually check whether the forefront oncoming vehicle entering the intersection is making a left turn or a right turn by looking at the blinking status of its turn signals. The inventors also found that collisions between a vehicle waiting to make a left turn and an oncoming vehicle frequently occurred at intersections where traffic is heavy. In view of these findings, the inventors came up with an idea for solving this problem.
Particularly on a road with heavy traffic, when a vehicle is waiting to make a left turn and if turning left of the forefront oncoming vehicle and second oncoming vehicle, both of which are entering the intersection, is clear to the driver of the waiting left-turn vehicle, there is no problem because the driver can discern the oncoming vehicles"" intentions by looking at the turn signals. The driver of the waiting left-turn vehicle cannot make a decision quickly until making sure of not colliding with oncoming traffic because there is a case where even when the forefront oncoming vehicle is making a left turn, the second oncoming vehicle may be going straight on (so that the driver of the waiting left-turn vehicle cannot start making a left turn until the driver actually recognizes the direction of the second oncoming vehicle). The inventors achieved the present invention by turning their attention to the finding that the driver of a vehicle waiting to make a left turn can prepare him/herself for making the turn ahead of time if he/she can tell that the second oncoming vehicle is making a left turn.
By turning attention to the fact that in conformity to traffic regulations, if any, a driver has to use a turn signal in advance if making a left turn or a right turn, the problem to be solved by the present invention is to provide a left-turn driving support device which enables the waiting left-turn driver to make a judgement without pressure by surely and accurately communicating the traveling intentions of a second oncoming vehicle following the forefront oncoming vehicle. Because the driver of the second oncoming vehicle entering an intersection to make a left or right turn must always use a turn signal, the driver of the vehicle waiting to make a left turn immediately is able to detect that the turn signal of the second oncoming vehicle is on if blinking of the turn signal can be detected as an optical signal on or near the road surface.
When the forefront oncoming vehicle entering the intersection goes straight on and the second oncoming vehicle goes straight on as well, a vehicle making a left turn has to wait for the vehicles passing through. Turning left in the intersection is easy when the forefront oncoming vehicle goes straight on and the second oncoming vehicle makes a left turn, and when the second oncoming vehicle makes a right turn, the driver can safely make a left turn with necessary caution for avoiding a minor collision with an oncoming vehicle turning right is required to make a left turn. Based on these actual conditions, a left turn can be made safely if the driver of the waiting left-turn vehicle can discern the traveling intentions of the second oncoming vehicle, whether it goes straight on or makes a left or right turn, rather than the traveling intentions or direction of the forefront oncoming vehicle.
An aspect of the present invention provides a left-turn driving support system for a driver of a vehicle waiting for making a left turn at an intersection where vehicles travel on the left side of a road, comprising a light-emitting device which emits light upon sensing blinking signals of a turn signal of a second oncoming vehicle following a forefront oncoming vehicle, which are about to enter the intersection, said light-emitting device being installed in a position from which the driver of the vehicle waiting for making a left turn is able to see emitted light from the light-emitting device. The light-emitting device may be a luminescent material.
As a luminescent material, preferred are a reflecting mirror 4a which reflects blinking of a turn signal, a reflective paint 4b which reflects blinking of a turn signal, an optical fiber which at one end 4c senses light from blinking turn signals and emits light from the other end 4d, and a combination of a means for sensing light from blinking turn signals and a means for emitting light based on the signals sensed by the means for sensing light.
As a position from which a vehicle waiting to make a left turn on the road surface is able to visually check a luminescent material which emits light upon sensing blinking of turn signals of the second oncoming vehicle, in the case of the second oncoming vehicle making a left turn, installing the luminescent material at or near the center line within the limits of 30 m, for example, and extending in a zone from an intersection entrance in the entering direction of the intersection, which may be a distance prescribed in traffic regulations for regular passenger cars for turning on a turn signal before making a turn, is preferable. In the case of the second oncoming vehicle making a right turn, installing the luminescent material near the intersection is preferable.
The present invention can also apply to a method for supporting a driver to achieve the above objects.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.